YAKYMIV, R. Y.; PROSKURIN, D. P.; OSTROVSKYI, V. L. Representations of relations with orthogonality condition and their deformations. Methods of Functional Analysis and Topology, [S. l.], v. 18, n. 4, p. 373–386, 2012. Disponível em: https://zen.imath.kiev.ua/index.php/mfat/article/view/528. Acesso em: 16 dec. 2025.